JP2797368B2 - Ion implanter - Google Patents

Description

The present invention relates to a so-called hybrid that electrically scans an ion beam to form a parallel beam and mechanically scans a wafer in a direction substantially perpendicular thereto. The present invention relates to a scan type ion implantation apparatus.

[Conventional technology]

 FIG. 8 shows a conventional example of this type of ion implantation apparatus.

That is, the ion beam 2 is electrically scanned in the X direction (for example, in the horizontal direction; the same applies hereinafter) by a scanning means (not shown), converted into a parallel beam, guided into an implantation chamber (not shown), and a holder 130 for holding the wafer 4. Is provided in the injection chamber, and this is mechanically scanned by the holder driving device 136 in the Y direction (for example, the vertical direction; hereinafter the same) perpendicular to the X direction in the injection chamber.

Briefly, the holder driving device 136 includes a holder erecting device 132 and a holder 130 that rotate the holder 130 between a vertical state for ion implantation with respect to the wafer 4 and a horizontal state for handling the wafer 4. A holder elevating device 134 that moves up and down in the Y direction and mechanically scans together with the erecting device 132 is provided.

In such an ion implantation apparatus, the angle of incidence of the ion beam 2 with respect to the wafer 4 is the same at each location in the wafer 4, unlike the case where the ion beam is electrically scanned simply in both the XY directions by the scanning means. There are features.

[Problems to be solved by the invention]

In the ion implantation apparatus as described above, in order to improve the throughput (processing capacity per unit time), the holder 130
A so-called dual type, in which two sets of driving devices are provided and the wafers 4 on the two holders 130 are alternately processed, may be considered.

In such a case, it is simpler, more compact, and more economical to provide a single beam line for the ion beam 2 (in other words, an electrical scanning system for the ion beam 2).

However, in the conventional ion implantation apparatus as described above,
Even if another holder 130 and holder driving device 136 are to be arranged symmetrically with respect to the ion beam 2 with respect to the one shown in the drawing (that is, arranged downward on the upper side of the one shown), the holder 130 is moved by the holder elevating device 134 to Y Since it only moves up and down linearly in the direction, the upper and lower holders 130 collide with each other.
130 and the holder driving device 136 must be largely separated from each other, and the device becomes large.

In addition, since the handling (mounting / demounting) position of the wafer 4 with respect to the holder 130 is greatly different between the upper and lower holders 130, the transfer line of the wafer 4 becomes two stages up and down, and the wafer 4 is handled downward with respect to the upper holder 130. For example, handling of the wafer 4 becomes very difficult.

Therefore, such an ion implanter is impractical, if at all possible.

SUMMARY OF THE INVENTION Accordingly, it is a main object of the present invention to provide an ion implantation apparatus which is of a hybrid type and has a single beam line as described above, and which can be miniaturized and which can easily handle a wafer. And

[Means for solving the problem]

One of the ion implantation apparatuses according to the present invention electrically scans an ion beam in the X direction to form a parallel beam and guides the ion beam into the implantation chamber, and moves the wafer in the Y direction substantially orthogonal to the X direction in the implantation chamber. An ion implantation apparatus having a structure for mechanically scanning, comprising two holders in an implantation chamber for respectively holding wafers, and two holder driving devices for scanning each holder in the implantation chamber in the Y direction. And each holder driving device has a hollow arm shaft that is supported so as to be able to take a posture substantially parallel to the traveling direction of the ion beam in the implantation chamber, and an arm that is mounted substantially at right angles to the arm shaft. A holder shaft at the distal end of the arm and supported so as to be substantially parallel to the arm axis, and driving means for rotating the arm axis in both forward and reverse directions;
An intermediate shaft rotatably passed through the arm shaft so that it does not rotate together with the arm shaft even when the arm shaft rotates, and a connecting means for connecting the intermediate shaft and the holder shaft at the same rotation ratio. And each of the holders is attached to the end of the holder shaft of each holder driving device and substantially perpendicular to the holder shaft.

[Action]

When the arm axis is rotated by the driving means of the holder driving device, the holder attached to the tip of the arm turns the wafer held there toward the ion beam,
Scanning is mechanically performed in the Y direction so as to draw an arc.

In that case, the intermediate shaft does not rotate even if the arm shaft rotates,
In addition, since the intermediate shaft and the holder shaft are connected at the same rotation ratio by the connecting means, the posture of the holder does not change even if the holder is scanned in a circular arc.

Moreover, since the arm and the holder move in an arc shape, the two holder driving devices can be arranged close to each other while avoiding mechanical interference with each other, and therefore, the size of the device can be reduced.

Further, since wafer handling for both holders can be performed under the same conditions, wafer handling becomes easy.

〔Example〕

FIG. 1 is a horizontal sectional view showing a main part of an ion implantation apparatus according to one embodiment of the present invention. In this example, the same mechanism is provided substantially symmetrically on the left and right of the beam line of the ion beam 2, so that the following description will be made mainly on the right side (the right side in the drawing).

An ion beam 2 which has been electrically scanned in the X direction and converted into a parallel beam is introduced from an introduction port 6a into an injection chamber 6 which is evacuated by a vacuum pump (not shown).

An example of such a scanning means of the ion beam 2 is shown in FIG. That is, the ion beam 2 extracted from the ion source 110 and subjected to mass analysis, acceleration, and the like as necessary.
And two sets of scan electrodes 112 and 1 to which scan voltages (triangular wave voltages) of opposite polarities are applied from the same scan power supply 116.
The scanning in the X direction is performed by the cooperation of 14 so that a parallel beam is emitted when emitted from the scanning electrode 114. However, unlike this example, the ion beam 2 may be scanned in the same manner as described above using a magnetic field.

Returning to FIG. 1, two holder driving devices 10 having the same structure are provided on the left and right of the processing chamber 6 as described above.

In each holder driving device, a vacuum seal bearing 12 is mounted on a side wall of the injection chamber 6, a support shaft 14 is penetrated therethrough, and a gear 16 is mounted on the atmosphere side (outside of the injection chamber 6). The support shaft 14 is rotated by the gear 18 as shown by an arrow A, and the holder 8 attached to the tip of the support shaft 14 via the arm 46 is set at the set injection angle position and the wafer 4.
It is designed to be driven to a horizontal position for handling.

On the vacuum side (inside the injection chamber 6) of the support shaft 14, the hollow arm shafts 40 and 46 are rotatably supported by vacuum seal bearings 386. The arm shaft 40 can take a posture substantially parallel to the traveling direction of the ion beam 2 by rotating the support shaft 14 to the state shown in the drawing.

At one end of the arm shaft 40, a pulley 36 is attached as a driving means, and the timing belt 32 connects the pulley 36 to the scanning motor 24 and the pulley 28 attached to the atmosphere side of the support shaft 14. The motor 24 rotates the arm shaft 40 in both the forward and reverse directions to rotate the arm 46 as shown by the arrow B, thereby moving the holder 8 in the Y direction substantially perpendicular to the X direction (in this example, the front and back sides of the paper). It scans mechanically.

A vacuum seal bearing 52 is attached to the tip of the arm 46,
The holder shaft 54 and the holder 8 are rotatably supported. The holder shaft 54 can take a posture substantially parallel to the traveling direction of the ion beam 2 by rotating the support shaft 14 as illustrated. A holder 8 for holding the wafer 4 is attached at a substantially right angle to the tip. In this example, the holder 8 includes a base 8a, a wafer retainer 8b for holding the wafer 4 therebetween, and a wafer receiver 8c for moving the wafer 4 up and down.

A pulley 50 is attached to the holder shaft 54. An intermediate shaft 42 is rotatably passed through the center of the arm shaft 40, and pulleys 34 and 44 are attached to both ends thereof. The pulleys 44 and 50 have the same diameter as each other, and are connected to each other by a timing belt 48 constituting a connecting means together with the pulleys. Therefore, the holder shaft 54 and the intermediate shaft 42 are connected at the same rotation ratio.

Further, the stepping motor 22 and the pulley 26 and the pulley 34 attached to the atmosphere side of the support shaft 14 are connected to each other by the timing belt 30. It can be rotated. However, rotation during injection is not performed. In this case, even when the arm shaft 40 rotates as shown by the arrow B, the intermediate shaft 42 does not rotate together with the arm shaft 40.

Note that a chain may be used instead of the timing belts 30, 32, and 48. In that case, a pulley associated therewith may be a chain gear.

The posture of the holder 8 during scanning will be described with reference to FIG. 3 as well. At that time, the motor 22 is stopped at this time, and the intermediate shaft 42 and the pulley 44 are stopped. In this state, when the arm 24 is rotated by the motor 24 via the pulley 28, the timing belt 32, and the pulley 36 in the clockwise direction, for example, as shown in FIG.
When viewed from the arm 46 side, the pulley 44 has rotated counterclockwise by θ ゜, and the pulley 50 having the same diameter as the pulley 44 connected by the timing belt 48 has a counterclockwise rotation θ when viewed from the arm 46 side.゜ Rotate. Accordingly, the holder 8 and the wafer 4 held thereon are scanned so as to draw an arc in the Y direction with the radius of the arm 46 as the radius, but the absolute rotation angle is 0 ° and the attitude is unchanged. Therefore, for example, when the wafer 4 is mounted on the holder 8 with the orientation flat 4a on the lower side, the orientation flat 4a is always on the lower side regardless of the scanning position of the holder 8. Moreover, since the ion beam 2 is converted into a parallel beam in the X direction as described above, for example, the ion beam 2
If the angular velocity of the arm 46 is controlled in proportion to the beam current, ion implantation with a uniform dose in the plane of the wafer 4 becomes possible.

In order to move the holder 8 to the handling position of the wafer 4 indicated by the two-dot chain line in FIG. 1, the holder 8 may be moved horizontally by the motor 20 and the holder 8 may be moved toward the wall by the motor 24. By doing so, the holder 8 eventually moves as shown by the arrow D.

Vacuum preparatory chambers 80 for loading and unloading (unloading and loading) the wafers 4 one by one between the inside of the injection chamber 6 and the atmosphere side are respectively adjacent to the left and right bottom portions of the rear of the injection chamber 6.

FIGS. 4 and 5 are cross-sectional views of the vacuum preliminary chamber 80.
Shown in the figure. FIG. 4 shows a state in which the vacuum side valve 88 of the pre-vacuum chamber 80 is closed and the atmosphere side valve 90 is open, and FIG. 5 shows a state in which the vacuum side valve 88 is open and the atmosphere side valve 90 is closed. However, FIG. 5 also shows a part of a wafer transfer device 60 described later for convenience.

More specifically, a vacuum preparatory chamber 80 that is evacuated by a vacuum pump 92 is provided at the bottom of the injection chamber 6. Atmosphere side valves 90 for partitioning from the atmosphere side are provided respectively.

The vacuum side valve 88 is moved up and down by an air cylinder 86 provided on the injection chamber 6, and the atmosphere side valve 90 is opened and closed by a lower air cylinder 102 via a guide shaft 98. still,
A lever 88 and an air cylinder 82 provided above the air cylinder 86 are for locking the air cylinder 86.

On the upper part of the atmosphere side valve 90, a turntable 94 on which the wafer 4 is mounted is provided.
The rotary table 94 is rotated by a motor 96 for orientation flat alignment of the wafer 4 and the like, and is rotated by a dual stroke cylinder 100 for handling the wafer 4.
It is raised and lowered to the stage.

Returning to FIG. 1 again, a wafer transfer device 60 having the following structure is provided in a portion from each of the vacuum preparatory chambers 80 to each of the holders 8 in a horizontal state as described above.

That is, referring also to FIG. 6, along the transfer path of the wafer 4 between the pre-vacuum chamber 80 and the holder 8 in a horizontal state,
A timing belt 68 is looped between two grooved pulleys 70 and 72. One pulley 70
Is connected to a motor 74 that rotates forward and reverse. On the upper and lower portions of the timing belt 68, a load-side transfer arm 61a and an unload-side transfer arm device 61b capable of mounting the wafer 4, respectively, are attached via connection fittings 66, respectively. Have been.

Further, in this embodiment, a ball spline is employed as guide means for guiding each of the transfer arms 61a and 61b to move along the timing belt 68 without rotating. That is, spline bearings 64a and 64b are attached to the roots of the transfer arms 61a and 61b, and two upper and lower spline shafts 62a and 62b penetrating therethrough are arranged in parallel with the timing belt 68.

Instead of such a ball spline, two normal guide shafts may be used. However, if a ball spline is used, the transport arm runs horizontally and stably with one spline shaft without rotating. Can guide you.

Although the spline shafts 62a and 62b are shown as round bars for simplification, they are actually round bars having a plurality of rolling grooves for balls or have different shapes.

Next, an overall operation example of the above-described ion implantation apparatus will be described focusing on the mechanism on the right side of FIG.

The holder 8 is moved to a horizontal position indicated by a two-dot chain line in FIG. 1 by the holder driving device 10, and the wafer receiver 8c and the wafer retainer 8b are driven by a driving device (not shown) to remove the previously mounted wafer 4. It is raised to a position where it is delivered to the lower unloading transfer arm 61b.

On the other hand, on the vacuum preparatory chamber 80 side, referring to FIG. 5, both upper and lower cylinders of the dual stroke cylinder 100 are operated to raise the turntable 94 significantly, and as shown by the two-dot chain line, the upper load side. Lift the uninjected wafer 4 to the position of the transfer arm 61a, and in that state
The timing belt 68 is driven by the motor 74 of 60,
The transfer arm 61a is simultaneously moved to the position on the vacuum preparatory chamber 80, and the transfer arm 61b is simultaneously moved to the position on the holder 8, and the wafer receiver 8c of the holder 8 is lowered to transfer the previously injected wafer 4 to the transfer arm 61b. On the other hand, the turntable 94 is also lowered on the vacuum preparatory chamber 80 side to place the uninjected wafer 4 on the transfer arm 61a.

Next, the motor 74 of the wafer transfer device 60 is rotated in the reverse direction, and the transfer arm 61b on which the implanted wafer 4 is mounted is moved onto the vacuum preliminary chamber 80, and the transfer arm on which the uninjected wafer 4 is mounted.
The wafer 61 is moved onto the holder 8, and only the upper cylinder of the dual stroke cylinder 100 is operated on the vacuum preparatory chamber 80 side to receive the wafer 4 from the transfer arm 61b by the turntable 64 (the state shown by the solid line in FIG. 5). ), The wafer 8 is received from the transfer arm 61a by the wafer receiver 8c on the holder 8 side.

Next, the motor 74 of the wafer transfer device 60 is again rotated in the reverse direction to move both transfer arms 61a and 61b to an intermediate standby position (the state shown in FIG. 1).
The wafer 8 is held down by lowering the wafer holder 8c and the wafer holder 8b, and the holder driving device 10 moves the holder 8 to an injection state shown by a solid line in FIG.

On the other hand, on the vacuum preparatory chamber 80 side, after the turntable 94 is lowered and the vacuum side valve 88 is closed, the inside of the vacuum preparatory chamber 80 is returned to the atmospheric pressure state and the atmospheric side valve 90 is opened (FIG. 4). State), the unloaded wafer 4 is carried out and the next unimplanted wafer 4 is carried in by the transfer arm device on the atmospheric side (not shown). At the same time, the wafer 4 on the holder 8 is irradiated with the ion beam 2 while mechanically scanning the holder 8 in the Y direction by the holder driving device 10 in the implantation chamber 6 as described above. An injection is performed.

Thereafter, the same operation as described above is repeated as necessary.

The relationship between the mechanism on the right side and the mechanism on the left side will be described. While scanning one holder (for example, the right side in FIG. 1) as described above, ion implantation is performed on the wafer 4 mounted thereon. In parallel with this, the other holder 8 can be kept horizontal to handle the wafer 4 (that is, take out the implanted wafer 4 and mount the uninjected wafer 4). That is, the ion implantation and the handling of the wafer 4 can be performed alternately in the two holders 8, and the loss time of the ion implantation and the handling is almost eliminated, so that the throughput is improved.

Moreover, according to the holder driving device 10 described above, unlike the holder driving device 136 in the conventional ion implantation device, each arm 46 and the holder 8 move in an arc shape, so that they mechanically interfere with each other. Therefore, the two holder driving devices 10 can be arranged close to each other while avoiding the problem, and thus the ion implanter can be downsized.

Further, the handling of the wafer 4 with respect to both holders 8 can be performed under the same condition as each other, that is, in this example, at the same height as each other and both of them can be performed with the surface of the wafer 4 facing upward.

FIG. 7 is a vertical sectional view showing a main part of an ion implantation apparatus according to another embodiment of the present invention.

In this embodiment as well, similarly to the embodiment of FIG. 1, the two above-mentioned implantation chambers 6 are introduced into the left and right of the implantation chamber 6 into which the ion beam 2 which has been electrically scanned in the X direction and converted into a parallel beam is introduced. Such a holder driving device 10 is provided so that each of the holders 8 on which the wafers 4 are mounted is mechanically scanned in the Y direction substantially orthogonal to the X direction.

However, in this embodiment, the wafer 4
Is different in handling. That is, a cassette driving mechanism for moving the cassette 120 by one pitch in the direction of the front and back of the paper below the holder driving device 10 in the injection chamber 6.
Each cassette drive mechanism 122 is provided.
On the top, a cassette 120 containing a plurality of wafers 4
Are respectively mounted via a vacuum spare chamber (not shown).

Further, a wafer vertical transfer device 124 is provided below each cassette drive mechanism 122, respectively. Each wafer vertical transfer device 124 has a push-up plate 126 which has a groove 128 at the tip end into which the end of the wafer 4 enters and which can be raised and lowered as shown by an arrow.
Can be transported one by one between the cassette 120 and the holder 8. Therefore, also in this embodiment, the handling of the wafer 4 with respect to the right and left holders 8 is possible under the same conditions.

An operation example of this embodiment will be described. The holder 8 on the right side of the figure is scanned in the Y direction by the holder driving device 10 as shown by the arrow E shown by the solid line, and the ion is implanted into the wafer 4 there. In the holder driving device 10, the arm 46 is rotated downward, and the wafer 4 already loaded in the holder 8 is transferred into the cassette 120 by the wafer vertical transfer device 124, and the cassette driving mechanism 122 The wafer 120 is driven by one pitch to mount the uninjected wafer 4 in the cassette 120 on the holder 8 and waits.

When the ion implantation for the wafer 4 on the right holder 8 is completed, the right arm 46 is rotated downward to exchange the wafer 4 for the holder 8 in the same manner as described above. Meanwhile, in the holder driving device 10 on the left side, the holder 8 is moved from the standby position (wafer replacement position) to the implantation position to perform a scanning operation and perform ion implantation on the wafer 4 there.

In the embodiment of FIG. 7, unlike the embodiment of FIG.
If the injection angle is not variable because there is no state in which the holder 8 is in a horizontal state for handling the wafer 4, the support shaft 14 described in FIG. It is not always necessary to provide a mechanism for rotating as described above.

In any of the embodiments shown in FIGS. 1 and 7, when it is not necessary to rotate the holder 8 stepwise, the holder driving device 10 does not necessarily need to be provided with a mechanism for that.

〔The invention's effect〕

As described above, according to the present invention, since each arm and the holder move in an arc shape, the two holder driving devices can be arranged close to each other while avoiding mechanical interference with each other. The size of the ion implantation apparatus can be reduced.

Further, the handling of the wafer with respect to the two holders can be performed under the same conditions, so that the handling of the wafer becomes easy.

As a result, it is possible to manufacture a practical type of a dual-type ion implantation apparatus that uses a hybrid scan method and one beam line.

[Brief description of the drawings]

FIG. 1 is a horizontal sectional view showing a main part of an ion implantation apparatus according to one embodiment of the present invention. FIG. 2 is a schematic plan view showing an example of an electrical scanning means of the ion beam. FIG. 3 is a view for explaining the attitude of the holder at the time of scanning by the holder driving device of FIG. 4 and 5 are cross-sectional views along the line II of FIG. 1, but in different operating states. FIG. 6 is a perspective view showing the wafer transfer device in FIG. FIG. 7 is a vertical sectional view showing a main part of an ion implantation apparatus according to another embodiment of the present invention. FIG. 8 is a perspective view showing a main part of a conventional ion implantation apparatus. 2 ... Ion beam, 4 ... Wafer, 6 ... Implantation chamber,
8 Holder, 10 Holder drive, 24 Motor
40 ... arm shaft, 42 ... intermediate shaft, 46 ... arm, 48 ...
Timing belt, 52 ... Holder shaft.

Claims (2)

(57) [Claims] An ion beam is electrically scanned in an X direction to be converted into a parallel beam and guided into an implantation chamber, and a wafer is mechanically scanned in a Y direction substantially orthogonal to the X direction in the implantation chamber. An ion implantation apparatus, comprising: two holders in the implantation chamber for holding wafers respectively; and two holder driving devices for scanning each holder in the implantation chamber in the Y direction, respectively. Are a hollow arm axis supported so as to be able to take a posture substantially parallel to the traveling direction of the ion beam in the implantation chamber, an arm mounted substantially at right angles to the arm axis, and a tip end of the arm. A holder shaft supported so as to be substantially parallel to the arm shaft, a driving means for rotating the arm shaft in both forward and reverse directions, and an arm shaft rotatably passed through the arm shaft. An intermediate shaft that is prevented from rotating together with the intermediate shaft, and coupling means for coupling the intermediate shaft and the holder shaft at the same rotation ratio. The ion implantation apparatus, wherein each of the holders is attached to a tip portion and substantially perpendicular to the holder axis. 2. A structure in which an ion beam is electrically scanned in an X direction to be converted into a parallel beam and guided into an implantation chamber, and a wafer is mechanically scanned in the implantation chamber in a Y direction substantially orthogonal to the X direction. An ion implantation apparatus, comprising: two holders in the implantation chamber for holding wafers respectively; and two holder driving devices for scanning each holder in the implantation chamber in the Y direction, respectively. Is a hollow arm axis supported substantially parallel to the traveling direction of the ion beam in the implantation chamber, an arm mounted substantially at right angles to the arm axis, and substantially parallel to the arm axis at the tip of the arm. And a driving means for rotating the arm shaft in both forward and reverse directions, and rotatably passed through the arm shaft so that even if the arm shaft rotates, it does not rotate with it. And a connecting means for connecting the intermediate shaft and the holder shaft at the same rotational ratio, respectively, and at a tip end of the holder shaft of each holder driving device, and the holder shaft The ion implantation apparatus, wherein each of the holders is mounted so as to be substantially orthogonal to the holder.